The invention relates to a method of cutting by means of laser radiation and to a device for implementing the method.
In connection with materials processing, it is known to conduct laser radiation--emanating from a laser generator--by way of beam guidance systems to the location of interaction and to there focus it, if required, by means of optical imaging elements in order to increase the power or energy density.
In that case, the cross section of the focus generally corresponds to a reduced image of the beam waist of the laser radiation in the resonator. In practice, this image is approximately point shaped. Prior art radiation guidance systems are configured either as articulated multiple-mirror arms or as light waveguides. Most of the light waveguides, particularly those operating in the ultraviolet or infrared range, still exhibit technical deficiencies with respect to the transmission of higher energy or power densities so that the desired energy or power values, which must lie sufficiently high above the starting threshold of the respective process, cannot be transmitted reliably.
When lasers operating in a spectral range from 150 nm to 11 .mu.m are employed for cutting structured materials which pose different resistances to the cutting laser beam--here called "composite materials"--and particularly insofar as hard organic tissue is concerned, there exists the additional problem that the focused beam, as a result of the respective texture, cuts to greatly differing depths--with respect to the same action periods.
German Unexamined Published Patent Application No. 1,565,144 discloses, for materials processing by means of laser radiation, to shape the laser beam with cylindrical lenses in order to drill rectangular holes.